Mercerization and finishing of textile fabrics



Patented Jan. 29, 1924.

EMILE AIl'GUS'IE FOURNEAU X, 0F MANCHESTER, ENGLAND.

MEBGERIZATION AND FINISHING OF TEXTILE FABRICS.

No Drawing.

To all whom it may concern:

Be it known that I, EMILE A GUSTE FOURNEAUX, a subject of the King of Great Britain and Ireland,,and resident of St. James Buildings, Oxford Street, Manchester, England, have invented certain new and useful Improvements Relating to the Mercerization and Finishing of Textile Fabrics, of which the following is a specification.

It is known that strong mercerizing effects may be produced on cotton fabrics by immersing them in a calcium thiocyanate solution, but though this action has been investigated by a number of careful. observers, no useful results were obtained mainly because the treatment in cold solutions does not offer any material advantage over the treatment with known agents, such as caustic soda, while the treatment with hot solutions leads to the fabric becoming stiff, rough and unpleasant to the touch. The object of the present invention is to provide a new process in which advantages are obtained with the aid of thiocyanates which are of great practical value and which completely avoid the disadvantages of the earlier attempts.

The invention comprises the mercerization of the fabric in the ordinary manner with alkali, before Or after or both before and after its treatment with a hot solution of calcium thiocyanate or hot solutions of other thiocyanates or mixtures of thiocyanates known to be solvents of cellulose.

My invention further comprises the impregnation of the fabric after meroerization with alkali in the ordinary manner, either with hot or cold calcium thiocyanate or equivalent solution, the action of the solution being effected or completed by passing the preferably wet fabric through an atmosphere of hot air, steam or vapor, then washing and if desired, drying or alternatively washing and if desired drying, again mercerizing with alkali, washing and again drying the fabric.

My invention further comprises the print ing of resists upon the fabric either before or after the mercerization treatment with alkali and before the treatment with thiocyanates (as above referred to) by impreghating, printing or padding the fabric with solutions of calcium or other thiocyanate or mixtures of thiocyanates known to be solvents of cellulose. a

M invention further comprises the print- Applicatipn filed February 2, 1923. Serial No. 616,606.

ing of resists .upon the fabric after the treatment with thiocyana-tes (as above referred to) by impregnating, printing or padding with solutions of calcium or other thiocyanates (such as mentioned before) before i the final mercerization treatment with alkali with or without tension.

My invention further comprises the printing of the resists (1) both before and after.

the first alkali treatment, (2) before and after the first alkali treatment and after the thiocyanate treatment, (3) before the first alkali treatment and after the thiocyanate treatment, or (4) before and after the thiocyanate treatment.

The steps as described in the three preceding paragraphs are to be understood as being optional.

In carrying my invention into efiect, in one convenient manner, I use calcium thiocyanate solutions either neutral or slightly acid (containing, say, 4% of acetic acid, although the invention is not limited to this acid or to this quantity). The solutions should be of such concentration as to boil between 128 and 150 'centigrade, but preferably nearer the lower point. The boiling point of the solutions is easily determined, and it has proved a thoroughly satisfactory test even in the case of the commercial products used in practice, which contain small amounts of impurities.v notably sodium thiocyanate, ammonium thiocvanate and calcium chloride, and mayvary slightly in composition. Solutions approaching the upper limit are over-saturated in the cold, so that neither the thiocyanate contents nor the density afford any reliable criterion in their case. Working with solutions boiling within the said limits, the temperatu're'of treatment may vary between 90 and 130 centigrade, as concentration, temperature and time are more or less interdependent. Thus highly concentrated solutions do not require (the time being the same) so high a temperature as more dilute solutions, and if a somewhat longer time be used, the temperature or concentration (or to some extent both) can be somewhat reduced, a reaction the frequency of which is well known to every chemist. Mixtures of solutions of calcium thiocyanates with solutions of other neutral salts which are not inercerizing agents, such as calcium chloride, may be used, provided they do not interfere with. the mercerizing capacity of the thiocyanate, but in general the effect obtained with such mixtures is less satisfactory than that obtained with calcium thiocyanate solutions. The alkali mercerization is carried out in the usual manner by passing at ordinary temperatures with or without tension, the fabric through a solution of caustic soda containing of caustic soda. Of course the strengthof this solution, as is well known, may vary between wide limits. If desired, the calcium thio-, cyanate solution may be replaced partly or entirely' by solutions of other thio cyanates, or mixtures of thiocyanates known to be solvents of cellulose, such as solutions of the strontium salt or of the magnesium salt boiling between 133 and 140 centigrade.

If a calcium thiocyanate solution be employed which boils between 120 and 128 centigrade, or if the temperature be keptbetween 60 and 90 centigrade with solutions boiling between 128 and 150 centigrade, the reaction is not complete but the partial effects obtained thereby may have commercial value.

Two explanatory examples are given here under of the application of the process, but the invention is not limited to the particulars or working conditions therein stated E sample 1.

' onds, say 7 to 10 seconds, to one minute.

The fabric is then washed with or without tension *or the tension may be applied immediately after washing and before drying. The effect obtained is a lustrous, soft and elastic permanent finish, which becomes harder on more prolonged treatment.

Example 2.

The fabric treated as per Example 1 is mercerized a second time with alkali, with or without tension. The effect produced is a smooth, lustrous and transparent permanent finish which is stiff, without being hard or harsh.

If desired, the alternate alkali and thiocyanate treatments may be repeated.

In another application of the invention, the fabric after mercerization with alkali in the ordinary manner with or without tension is impregnated with calcium thiocyanate solution of suitable concentration and then passed through an atmosphere of hot steam, va our or air in which the reaction of the ca ciuln thiocyanate upon the cellulose 1s thiocyanate solution used will depend upon the fabric itself (thickness, tightness of before referred to may be substituted therer for. The concentration of the calcium weave, etc.), the amount of solution present whilst it is being exposed to the heated atmosphere and the amount of drying which takes place during such heating.

The effects obtained may be enhanced by the printing of resists upon the fabric either before or after the first alkali treatment, or before the second alkali treatment, and/or by the printing of resists upon the fabric at any two of the said stages in the complete process. The printing pastes used for this purpose may be thickened with any of the ordinary thickening agents such as starch gum, glue, albumen, etc., and may be used as such, or with the addition of pigments, or of colouringmatters together with their usual assist-ants and/or mordants.

The resists, pigments, dyes and the like can be printed on the fabric in suitable designs.

In some cases, it is desirable to subject to this treatment or to the thiocyanate treatment, certain defined areas only of the enthe fabric, thereby producing a brocade effect. As a particular illustration, the entire area of the fabric may be mercerized with alkali with or without tension, then printed in certain defined areas with a paste containing a thiocyanate and dried. The printed fabric is then subjected to heat in. the presence of moisture by any of the means described herein, but preferably by the action of steam in a steam a er, as that operation also serves to fix co ours such as Vat colours which may be printed at the same time as the thiocyanate paste in fitted atterns or otherwise. washed and preferably driedand again sub mitted to an alkali mercerizing operation, washed and dried. After the final washing and drying, the fabric resembles a brocade, the printed portions ofthe area being rendered more or 1cm transparent and thus in marked contrast to the unprinted portion, which retains its mercerizing lustre. The ageing method requires a certain amount of care to prevent tendering of the fabric.' A1- ternatively, the fabric carrying the thiocyanate solution or paste may be passed through a hot liquid, the boiling point of which 'is above the temperature required for the treat- The fabric is t on I relatively dry atmosphere, such as hot air or dry steam, there is usually an opportunity for the solution to lose moisture, and thereby become further concentrated. This shouldbe taken into account when preparing the original thiocyanate solution or paste.

ing agent enhances the effect of the process, due to the local action of thiocyanate The use of cellulose as the thicken- (in combination with alkali mercerization treatment), and this makes the effect of the treatment more permanent.

The paste containing cellulose should be of a consistency suitable for printing purposes. The amount of thiocyanate to be present therein may vary and depends on the degree of drying during the heat treatment, on the effect which is to be achieved and on the character of the fabric which is being treated. The proper amount has to be determined by experiment from case to case.

E mample 3.

The fabric is mercerized under tension with alkali according to the usual process, washed and dried. It is then printed with, say, starch paste in those places where it is intended to produce a white resist, and with pastes containing colours, in those places where it is intended to produce coloured resist effects. Most of the colours in common use in calico printing are suitable for the process described in this example. The colours are developed or fixed in the usual way, e. g., by ageing or steaming. The fabric either printed with paste or with paste containing colours, is then submitted to a treatment with calcium thiocyanate solution as described in Example 1. Alternatively, before the thiocyanate treatment the fabric may be washed or submitted to any of the customary after-treatments e. g., fixation with tartar emetic, care being taken that these operations are conducted in such manner as to leave sufficient of the resisting agent-4n the present instance starch-on the fibre. The printed portions remain opaque and retain much of their merceriz ing lustre, especially if the starch has been removed by malting subsequent to the thiocyanate treatment, whereas the nonprinted portions assume the typical finish described in Example 1.

. Emample 4. Fabric treated according to Example 3 is mercerized a second time with alkali with or without tension, or alternatively the alkali may .beapplied by printing with a suitable pattern. For the purposes of this special process only those printing colours can be used which are suitable for the ordinary crimping process. The effect produced is as follows :-The printed portions of the fabric-remain opaque and retain much of their mercerizing lustre, the unprinted portions assume-the finish described in Example 2 in those portions which have been treated with alkali, and in the portions which have not been treated with alkali they retain the finish described in Example 1..

Ewample 5.

The fabric is mcrcerized with alkali under tension, washed and dried. It is then printed, with, say, starch paste in those places where it is intended to produce a white resist and with printing colours or pastes such as are known to be suitable for the'o-rdinary crimping process. The colours are then developed in the customary manner e. g., by ageing or steaming. The fabric is then printed with a calcium thiocyanate solution in which cellulose has been dissolved, is dried, subjected to heat in the presence of moisture, and thereafter niercerized with caustic alkali, as hereinbefore described. Those parts which have been printed with thiocyanate assume a glassy and transparent aspect, except in those parts of the fabric which have been printed with the white or coloured resist. The permanency of the finish in the products obtained by my process is very remarkable and of very great importance.

ll claim 1. A permanently lustrous, soft and elastic cotton fabric produced from ordinary cotton fabric by alternate treatment with caustic soda and thiocyanates.

2. A permanently lustrous, soft and elastic cotton fabric produced from ordinary cotton fabric by treatment with caustic soda and mixtures of thiocyanatcs.

3. A cotton fabric in which portions of the fabric have been mercerized to have a glossy finish and other portions altered to have a lustrous, soft, elastic permanent finish.

t. The process which comprises the treatment of cotton fabric with caustic soda for inercerization and the treatment of the fabric with a hot solution of a thiocyanate capable of dissolving cellulose, such treatments being conducted in any desired order.

5. The process which comprises the mercerization of cotton fabric with caustic soda and the treatment of the mercerized fabric .with a calcium thiocyanate solution, the

moisture, such treatments being conducted in any desired order,

6. A process which comprises treating cotton fabric by mercerization with alkali,

thereafter treating with a hot solution of a thiocyanate capable of dissolving cellulose, and thereafter again mercerizing with alkali. g

7. A process which comprises treating cotton fabric by mercerization with alkali, thereafter treating the same with a solution of a thiocyanate which is capable of dis-.

9. In the process of claim 8, the use of a cellulosic material dissolved in the thiocyanate as the thickening agent.

10. An alkali mercerized I which has been printed in certain defined areas with a solution of thioc anate, ex-

posed to the action of heat in t e presence ,ing the mercerizing lustre, the printed portion becoming more or less transparent and assuming a glassy lustre.

11. An alkali mercerized cotton fabric which has been printed in certain defined areas forming a pattern with a solution of a thiocyanate, and printed in other defined areas with colours, submitted to the action of steam in a steam ager, washed and again mercerized with alkali, the fabric presenting the appearance of a brocade, the unprinted portions and the portions printed with colour retaining the mercerizing lustre, the portions printed with thiocyanate being more or less transparent and having a glassy lustre.

12. Ornamented mercerized cotton fabrics having in places forming pattern, a lustrous, more or less soft and elastic finish and being coloured in other places forming a pattern,

cotton fabric the coloured places retaining the original mercerizing lustre.

13. Ornamented mercerized cotton fabrics having in places. forming a pattern a smooth, lustrous and transparent permanent finish which is stiff Without being hard or harsh and being coloured in other places forming a pattern, the coloured places retaining the original mercerizing lustre and finish.

14. Printed mercerized fabrics in which the coloured and some of the uncoloured portions possess a mercerizing finish and,

lustre, while in other of the uncoloured ortions the fibres have assumed a smooth, ustrous and transparent permanent finish which is stiff without being hard. or harsh.

15. The process which comprises mercerizing a fabric with alkali, printing it with starch paste in certain places and with colour in others, developing or fixing the colours and submitting the fabric thus treatedto treatment with calcium thiocyanate solution.

16. In the rocess of claim 15, washing the fabric be ore the thiocyanate treatment after fixing the colours, leaving suflicient of the resisting agent on the fibre, for bein efiective during the treatment of the fa ric with thiocyanate solution and finally again washing and drying the fabric after the 'thiocyanate treatment.

17. The process which comprises mercer izing with caustic soda the fabric obtained according to claim 15 and thereafter washing and drying it.

18. The Y izing a fa ric with caustic soda, washing and drying it, printing it with starch paste to produce a white resist and printing with coloring materials for colour effects, developing the colours and printing the fabric with a calcium thiocyanate solution containing cellulose, drying and steaming, ex-

posing it to the action of steam in the steam I ager, washing, mercerizing again with caustic soda, washing and drying it.

In testimony whereof I have signed my name to this specification.

EMILE AUGUSTE FOURNEAUX.

rocess which comprises mercer- 

